1. Technical Field
The present invention relates to a thin film transistor (TFT) substrate and a method for manufacturing the same, and in particular to a TFT substrate and a method for manufacturing the same that prevent a metallic oxide active layer after film forming from being polluted by moisture in the environment and chemical liquids in manufacturing processes.
2. Related Art
With the gradual progress of a display technology, the assistance of displays makes life more convenient for people. To meet a demand for lighter and thinner displays, flat panel displays (FPDs) become the mainstream at present. Among many FPDs, liquid crystal displays (LCDs) have advantageous features such as high space utilization efficiency, low power consumption, zero radiation, and low electromagnetic interference, and are therefore popular among consumers. In particular, structure design or material selection of TFT substrates, which are heavily used in displays, directly affects performance of products.
Generally speaking, a TFT in the TFT substrate at least has members such as a gate electrode, a source electrode, a drain electrode, and a channel layer, where the electrical conductivity of the channel layer can be changed by controlling a voltage of the gate electrode, so that an electrically connected (Switch On) state or an electrically insulated (Switch Off) state is formed between the source electrode and drain electrode. Materials of channel layers are mostly amorphous silicon (a-Si). However, in recent years, indium gallium zinc oxide (IGZO) is gradually replacing the a-Si, because compared with the a-Si, the IGZO can reduce the size of the TFT, improve an aperture ratio of pixels of a liquid crystal panel, and easily achieve doubled resolution and ten-time-faster electron mobility.
However, after manufacturing processes such as film forming, lithography, and etching, the IGZO is subject to a stripping process, in which a photoresist attached on the IGZO is stripped; at this time, a surface of the IGZO is not protected by the photoresist, and therefore is prone to pollution of moisture in the environment and a chemical liquid in the stripping process, and an electrical property of the IGZO is greatly affected.
Therefore, it is necessary to provide a TFT substrate and a method for manufacturing the same to prevent the IGZO from being polluted by moisture in the environment and chemical liquids in processes.